On Wed, Jun 5, 2013 at 11:35 AM, Lubomir Popov <lpo...@mm-sol.com> wrote: > Hi Nishanth, > > On 05/06/13 17:01, Nishanth Menon wrote: >> On Wed, Jun 5, 2013 at 3:03 AM, Lubomir Popov <lpo...@mm-sol.com> wrote: >>> Hi Tom, >>> >>> On 05/06/13 00:06, Tom Rini wrote: >>>> On Mon, Jun 03, 2013 at 10:58:27PM +0300, Lubomir Popov wrote: >>>>> Hi Lokesh, >>>>> >>>>>> Hi Lubomir, >>>>>> On Thursday 30 May 2013 07:56 PM, Lubomir Popov wrote: >>>>>>> Hi Lokesh, >>>>>>> >>>>>>> On 30/05/13 16:19, Lokesh Vutla wrote: >>>>>>>> From: Balaji T K <balaj...@ti.com> >>>>>>>> >>>>>>>> add dra mmc pbias support and ldo1 power on >>>>>>>> >>>>>>>> Signed-off-by: Balaji T K <balaj...@ti.com> >>>>>>>> Signed-off-by: Lokesh Vutla <lokeshvu...@ti.com> >>>>>>>> --- >>>>>>>> arch/arm/include/asm/arch-omap5/omap.h | 3 ++- >>>>>>>> drivers/mmc/omap_hsmmc.c | 26 >>>>>>>> ++++++++++++++------------ >>>>>>>> drivers/power/palmas.c | 25 >>>>>>>> ++++++++++++++++++++++++- >>>>>>>> include/configs/omap5_common.h | 4 ++++ >>>>>>>> include/configs/omap5_uevm.h | 5 ----- >>>>>>>> include/palmas.h | 6 +++++- >>>>>>>> 6 files changed, 49 insertions(+), 20 deletions(-) >>>>>>>> >>>>> [snip] >>>>>>>> + /* set LDO9 TWL6035 to 3V */ >>>>>>> LDO9? TWL6035? If this function is used on the DRA7xx boards only (with >>>>>>> TPS659038), you should add some comment above. >>>>>> Ok ll add the comment. >>>>>>> >>>>>>>> + val = 0x2b; /* (3 - 0.9) * 20 + 1 */ >>>>>>> Why not use definitions for the voltage? You could take them from >>>>>>> http://patchwork.ozlabs.org/patch/244103/ where some values are >>>>>>> defined. >>>>>> Yes, Ill rebase this patch on top of your patch and use those defines. >>>>> Please be aware that my above mentioned patch has not been reviewed/ >>>>> tested/acked/nacked/whatever by nobody (except possibly a quick look by >>>>> Nishanth Menon, who had some objections). I wrote it when bringing up a >>>>> custom OMAP5 board, and most probably it shall not go into mainline in >>>>> its current form, if ever. I gave it only as an example of how things >>>>> could be done cleaner. Feel free to use the code as you wish, but I'm >>>>> afraid that applying it as a patch to your tree and basing upon it might >>>>> run you into problems when you later sync with mainline. >>>>> >>>>> Tom, your opinion? >>>> >>>> OK, so at the time it was "nothing will really use this code except test >>>> functions". Looks like we have a use for mmc1_ldo9 code at least, so >>>> lets rework the first patch for adding that + cleanups wrt constants. >>> Well, I'm not quite sure that this LDO9 function would be the only one >>> used (or LDO1 on the DRA7xx board). Judging from omapboot for the OMAP5 >>> boards for example, SMPS7 (it delivers the common 1.8 V I/O supply) is >>> set to 'Forced PWM' mode in order to reduce board noise - there sure has >>> been a reason to do so and sacrifice converter efficiency. Therefore I >>> added similar functionality in my patch to the Palmas driver (and am >>> explicitly calling it in my board init). >>> The option to bypass LDO9 on OMAP5+TWL603x boards seems quite mandatory >>> as well, if hardware is designed such that the SD card socket has a >>> separate fixed 3.3 V supply which also powers the LDO9 input (the >>> uEVM for example). On the DRA7xx+TPS659038 board the power scheme is >>> different and this does not apply. >>> >> >> I hate this code for many reasons - >> a) hsmmc is used on many OMAP and DM platforms to my knowledge. >> b) what is being done here is to power on the LDO supplying MMC. > Sorry, but I can't get if hsmmc is discussed here, or power. > > For OMAP5+TWL603x the LDO powering MMC (actually the removable card > interface only; eMMC is another story) is turned on automatically at > power-on by the PMIC sequencer, with a default voltage and mode -- > otherwise we would not be able to boot from a card (ROM code does not > touch the PMIC at all). We are talking here about the possibility to > have additional control over this LDO, which should be board-specific, > I agree. On the OMAP5 boards, for example, the call to > palmas_mmc1_poweron_ldo() from within omap_hsmmc actually does not > turn on LDO9 - it is on at this moment anyway. The call just makes > it switch from the default bypass mode (with Vout = Vin = 3.3 V) to > regulation mode and Vout = 3.0 V. Why is this done is yet another > question; to me it seems useless (and possibly wrong) when the card > is powered with a fixed voltage of 3.3 V. > Therefore it seems reasonable to count on the PMIC defaults and > remove this call from omap_hsmmc altogether, thus disengaging the > PMIC driver from hsmmc, at least for OMAP5. > > For OMAP4 things are somewhat different. Here the TWL6030 PMIC powers > both the OMAP interface and the card socket, and in addition can > automatically power off the MMC LDO upon detecting card removal. > ROM code *does* access the MMC LDO to turn it on and set it to 3.0 V > (it starts by default at 1.8 V), but only if booting from a card. > So here the call to PMIC driver should stay. > > Other OMAPs and derivatives - other scenarios. > > Anyway, omap_hsmmc.c is built for TI platforms only. If you mean > the #ifdefs here, yes, things could be cleaned up by moving the SoC- > specific pbias stuff to the corresponding board files (with the > expense of redundancy), but this is quite an amount of work... I'm > not volunteering... ;) Moreover, this particular patch is not mine. > I understand approximately why we do this, but there are more than a single MMC on OMAP, in general. and different platforms use different PMICs I am just looking at http://patchwork.ozlabs.org/patch/248928/ and I am like - wait a minute, how many #ifdef #else is one going to add per MMC/board? switching on LDOx meant for MMC1 will work for MMC2? makes no sense to me. is'nt better for struct mmc to have a function pointer which is populated by the board(depending on PMIC) to setup voltage necessary?
the trouble I have is not that omap_hsmmc is meant for TI SoCs. I get that. but the fact that the code is starting to look so convoluted that it will ONLY work on TI boards!!! I dont get that! Regards, Nishanth Menon _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
